def main():
    while True:
        try:
            x0, y0, r = map(int, input().split())
            s = 0
            for x in range(-r, r+1):
                for y in range(-r, r+1):
                    if x**2+y**2 == r**2:
                        s += 1
                        # print(x, y)
            print(s)
        except:
            break


if __name__ == '__main__':
    main()
